A distributed base station system includes a radio remote unit (RRU, Radio Remote Unit) and a base band unit (BBU, Base band Unit), where the RRU is also called an RRH (Radio Remote Head) in certain contexts. In embodiments of the present invention, the name “RRU” is taken as an example. Referring to FIG. 1, an RRU is generally installed on a tower, connected to an antenna through a feeder, and connected to the tower through a ground line, and therefore, is grounded through the tower. The BBU is located in a remote equipment room (or another similar shelter) under the tower, and is connected to the RRU through a fiber to receive and send signals to be processed.
To supply a direct current to the RRU and the BBU, the base station system needs to be equipped with a power supply system. As shown in FIG. 1, in the prior art, the RRU and the BBU are generally powered by a power supply system (also called a power source system or a primary power supply). Specifically, a direct current power supply output by the power supply system provides power for the RRU on the tower through a shielded cable. The RRU is located on the tower, and the tower is vulnerable to lightning strike. When the tower is struck by lightning, a strong lightning current tends to flow into the RRU through the ground line of the RRU and flow into the power supply system through the shielded cable connected to the RRU to damage the RRU and the power supply system. To prevent the RRU and the power supply system from being damaged by lightning strike on the tower, a lightning protection circuit is generally set on the RRU and the power supply system side in the prior art. FIG. 2 is a schematic diagram of a lightning protection setting on the RRU side in the prior art. A lightning protection component (such as a varistor, a gas discharge tube, a transient suppression diode) is connected between a −48 V signal line and the earth, and between an RTN signal line and the earth, respectively, to meet lightning protection requirements. FIG. 3 is a schematic diagram of a lightning protection setting on the power supply system side in the prior art (assuming that the power supply system here is a rectifier, where the rectifier rectifies an alternating current power supply and outputs a direct current power supply). The positive pole of the rectifier is grounded, and a −48 V signal line and an RTN return line are each connected to a lightning protection component on the ground in a way shown in the figure.
In the process of implementing the present invention, the inventor finds at least the following defects in the prior art:
In the prior art, a lightning protection module is required on both the RRU side and the power supply system side, which requires a certain cost and increases the size of the RRU and the device on the power supply system side.